1. Field of the Invention
The present invention relates to a display apparatus and a control method therefor; more particularly, to a display apparatus possessing multiple display units and a control method therefor.
2. Description of the Related Art
In recent years, with the spread of digital broadcasting and the Internet, electronic apparatuses possessing functionality capable of displaying information obtained through such medium have been widely adopted.
For example, Japanese Patent Laid-Open No. 2007-053518 discloses a television having, in addition to a main display that displays broadcast programs, a sub-display that displays program information, and displaying on the sub-display, when the television is in a stand-by state, program information which conforms to information related to a viewer's preferences.
Meanwhile, current environmental problems have created a strong demand for reductions in the energy consumption of electronic devices. For example, Japanese Patent Laid-Open No. H11-231850 discloses a method whereby, when a display apparatus having a plurality of CPU's enters a standby state, a sub-CPU controls display of a screensaver while a main CPU is entered a suspend state, thereby suppressing energy consumption when in the standby state.
In the television apparatus disclosed in Japanese Patent Laid-Open No. 2007-053518, display control of both the main display and the sub-display is performed by the same control unit. Therefore, even when in the standby state and only the sub-display is displaying information, reduction in energy consumption stops with the main display.
From the perspective of reducing energy consumption while in the standby state, it may be thought effective to use multiple control units and use a sub-control unit to perform control of the sub-display, like the method described in Japanese Patent Laid-Open No. H11-231850. However, if, while in the standby state, the information to be displayed exists in the main control unit, even if there are multiple control units, the main control unit cannot enter suspend state and no effective difference in energy consumption is achieved over the case of having a single control unit.
This problem may be solved if the sub-control unit could be provided the same information that the main control unit has. However, providing the same information to multiple control units in order to carry out display while in the standby state is inefficient because it requires an increase in memory usage, and redundant information processing.